Thesis (M.S.)--Ohio State University. / Includes bibliographical references (leaves 64-76). Available online via OhioLINK's ETD Center.

The determination of the pressure distribution generated along the arc of contact between the rolls and workpiece during the rolling process has been a subject of interest to researchers for many years. Existing rolling theories make assumptions and include simplifications which are not often substantiated by direct measurement techniques in which pressure transducers are located within the roll surfaces. Such techniques are effective but prohibitively expensive since they render the rolls useless for rolling. A technique has been developed in which the pressure distribution and roll separating load are determined from consideration of the elastic deformation of the rolls during operation. By interrupting a rolling pass before completion, the shapes of the deformed rolls are imparted to the workpiece surface. Accurate measurement of the imparted profiles at several sections across the width of the workpiece allows the extent of the elastic deformation of the roll to be determined. An analytical solution based on solid body contact theory was used to determine the pressure distribution responsible for the elastic deformation along each section. The solution incorporates experimentally determined parameters and functions relating to specific mill-stands and schedules. Initial experimental work was undertaken in which the proposed technique was applied to the quasi-static indentation of flat and inclinedstrip specimens. Having established the basic features of the method relating to these modes of deformation the technique was then applied to the cold rolling process in the form of interrupted rolling passes. Tests were undertaken using a two-high laboratory rolling mill reducing the thickness of mild steel strip workpieces. Comparisons between the predicted pressure profiles using the technique developed and those determined by others using pressure transducers show close similarities. A comparison between the predicted roll separating loads and those determined experimentally show a reasonable correlation.

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The material transport system in an open pit mine significantly affects the capital and operating costs. All truck haulage is the most common and is a reliable and flexible transport system. On the other hand, this system is very expensive and can cost up to 50% of total mining costs. Its cost is continuously increasing due to the inflation of the fuel, tire, and labour expenditures. In-pit crushing and conveying is an alternative transport system which requires a higher initial investment but gives substantial savings in operating costs. An evaluation of the all truck system versus the in-pit crushing and conveying system has been performed by means of a simulation of both transport systems in the same mine model. Results of the simulation and the data obtained from the feasibility studies provided input for an economic comparison of the alternative transport systems. A cash flow analysis showed that the in-pit crushing and conveying system was competitive with the all truck system, giving a payback within four years and resulting in total costs over 30% lower than those of an all truck system. Three computer programs, written by the author, have been used to analyse the mine model: (1) Open Pit Simulation Program - to model a hypothetical mine and simulate its haulage operation over the mine life, (2) Off-Highway Truck Simulation Program - to simulate the truck haulage on average annual routes in terms of the operating time and fuel consumption for the estimation of the truck fleet size and the fuel cost, (3) Cash Flow Analysis Calculation Program - to compare costs of the alternative transport systems over the whole period of a mine life. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

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